Customs enforcement powers entrusted to border security officers within designated border belt, enabling specified search and seizure functions. Authorizes officers and subordinate officers of the Sashastra Seema Bal to perform specified functions of an officer of customs, with designated ranks matched to identified customs powers including search and seizure and related procedural provisions. The delegation is territorially limited to the belt along the Indo Nepal and Indo Bhutan borders in specified States and to areas of the Sashastra Seema Bal's operation as set out in the Schedule.